Ionic conductivity of scandia stabilized zirconia and alumina composites

This paper analyses the conductivity data of composite electrolytes in the 6ScSZ-Al2O3 system. The system provides a heterogeneous solid electrolyte in which the grain conductivity remains unaffected, whereas the grain boundary conductivity increases up to 20 wt% of Al2O3. The bulk conductivity, which includes contributions from both grain and grain boundary conductivity, therefore shows an enhancement with Al2O3 addition. The enhancement is explained on the basis of space charge formation at the ScSZ-Al2O3 boundaries. The conductivity of these composite specimens decreases when the Al2O3 concentration is increased to 30 wt%.